Power over Ethernet (PoE) is a technique for sending power over Ethernet cables. PoE follows IEEE standards including 802.3af and 802.3at. A device that provides power is called a power sourcing equipment (PSE), and a device that draws power is called a powered device (PD). A PSE may be an endpoint that provides data and power, such as a network switch or router, or a midspan that provides power but passes through data. PDs include IP phones, wireless access points, and security cameras.
Use of the same reference numbers in different figures indicates similar or identical elements.